Custom Field with default value not return all the time

Hello, I am looking for help, I define a cart custom field and assign a default value, but the value is not returning all the time, just in one order, I generate the custom field with the Shopify UI tool and add to my cart Liquid template, the code is the follow,

kcastillop4u_0-1638830468664.png

recently I change the default value to ‘Sales Rep Number’ instance to 9999 and I will wait for the result,

Any comments are welcome,

Regards